Fight for your life, if a person is trying to kidnap you it is not to buy you an ice cream cone.  If anyone puts there hands on you or comes after you in a threatening way you should resist and fight back.

You can't increase the dogs height, before you get a dog, you should always look at its parents, their size and shape will determine how large or small your dog would be.

In most places it is illegal to train your dog to attack.  If your dog does attack someone, even if you intentionally do it can be a felony. In other words, you can be charged with maiming.  Pits have bad reps already, why would you want it to attack?

The dog could have sprained or pulled a muscle whilst running.